An Etymological Dictionary of Astronomy and Astrophysics

To state with assurance, confidence, or force; state strongly or positively; affirm.

Etymology (EN): From L. assertus, p.p. of asserere/adserere “to claim, lay claim to, declare,” from → ad- “to” + serere “to join together, range in a row,” from PIE root *ser- (2) “to line up.”

Etymology (PE): Sotvârdan from sotvâr, ostovâr “firm, reliable,” Mid.Pers. awestwâr, ôst “firm, reliable,” O.Pers./Av. sta- “to stand; set,” (Av. hištaiti, cf. Skt. sthâ- “to stand,” Gk. histemi “put, place, weigh,” stasis “a standing still,” L. stare “to stand”); PIE base *sta- “to stand.”